Refrigerating apparatus.



FREDERICK G. KEYES, 01E BOSTON, MASSACHUSETTS;

REFRIGERATING APPARATUS.

Specification of Letters Patent.

Patented Feb. 41:, 19119.

Application filed January 17, 1918. Serial No. 212,313.

To all whom it may concern:

Be it known that I, FREDERICK G. KEYES, a citizen of the United States, residing at Boston, county of Suffolk, and State of Massachusetts, have invented certain new and useful Improvements in Refrigerating Apparatus, of which the following is a full, clear, and exact description.

To lead to a more ready comprehension of the nature and purposeofthe invention upon which is based my present application for Letters Patent, the more detailed description of the device embodying the same may be prefaced by asomewhat elementary discussion of the conditions with which it deals and the objects which it seeks to accomplish.

In all refrigeration machines of the absorption type in which the solution of absorbent and refrigerant is alternately heated and cooled, the cooling of the latter must occur during thereabsorption period of the cycle, to create a difference in pressure ofthe refrigerant over the absorbent in one portion of the apparatus and over the liquid refrigerant in another. complete absorption is a prime necessity if efl'ective refrigeration is to be secured, and for this purpose the refrigerant vapor is led into the absorbent as far under the surface of the latter as possible. A check valve is provided to prevent vapor returning to the still containing the absorbent by the path over which vapor reaches the refrigerating chamber during distillation, otherwise there would be no difference of pressure produced to c'ause the refrigerant vapor to bubble into the absorbent. Another check valve is, of course, necessary in the path leading the vapor into the absorbent. otherwise the absorbent would be forced over into the refrigerating chamber.

Assume now the conditions existing-in the apparatus at the instant when heat is withdrawn from'the still and cooling applied to the absorbent. There is at this moment no difference in pressure between the still liquor and that in refrigerating chamber, but in fact an equilibrium of pressure exists. As the still is cooled, however, the vapor pressure of the absorbent is lowered, but equilibrium must be established between the substantially pure refrigerant vapor in the dead space above the absorbent and the refrigerant in the solution. This equilibrium may be To secure rapid and -culation should be a very rapidly attained, of course, by mechanically agitating or stirring the solution so as to continually bring fresh surface of absorbent liquor into contact with the dead space vapor and so lower the'back pressure, but otherwise the process is a-slow one.

The purpose of my invention is to accomplish automatically and without movement of mechanical parts what would result readily from stirring or shaking of the still, and while the invention is generally applicable to apparatus of this character, I have illustrated it in connection with a special apparatus which may be more conveniently referred to in describing it.

Let it therefore be assumed that the still is of the upright type, having a length equal to several diameters and that there is a copper box Or receptacle in the dead space therein above the solution. From the lower periphery of this box several tubes of small bore lead radially with their ends directed toward the walls of the still where any liquor discharge from them would flow over or be sprayed upon the cooling coils within the still which may extend into the dead space.

From the bottom of this box leads a pipe up through its upper end and out of the still where it is formed into a few coils co-axially disposed and surrounded by a jacket through which water may be circulated. This cirpart of the still circulatory system so tha it does not flow during the distillation period. Finally this pipe passes into the bottom of another box or receptacle of. somewhat larger dimensions than the first, and arranged outside the still. This box contains a baffie system near its outlet to prevent the spray being carried over through the connecting pipe to the condenser and thence to the refrigerating chamber.

The dead space box is below the top of the still, but the tubes extendingfrom it dip slightly below the surface of the absorbent, so that when distillatio'n begins, liquor will be forced into the bafiied box above the still until the level of liquor in the still falls .below the open ends of the small bore tubes. Thereafter hot vapor will blow through the liquor contained in the bafiied box and cause its temperature to keep pace with that of the, still liquor.

placed immediately I At the end of the distillation portion of the cycle, the cooling water which is then caused to flow causes the pressure in the still dead space to fall to a slight extent, and liquor begins to pass from the baffled box which being cooled in transit finally flows down the walls of the still over the cooling coils in the dead space. The bore of the pipes leadingfrom the dead space box is so proportioned that the liquor does not pass through this space so rapidly as not to cause complete absorption.

It will be observed that there is still the vapor in the warm baffled box which when the liquor has flowed out might permit vapor to pass into the dead space, but as the pipe leading from the dead space box comes through its top, this vapor is compelled to bubble through the small quantity of cooled liquor left in the bottom of the latter and is there absorbed.

From what has been stated, it is manifest that with the arrangement discribed a rapid absorption of the vapor in the dead space in the still is brought about, and a prompt setting up of a maximum working difference of pressure essential to effective refrigeration is accomplished.

More specifically the apparatus which I have described and illustrated in the annexed drawing as a means of carrying out this invention comprises a still A having a heating coil B and an interior cooling coil C. In the upper 'part of the still is the box or receptacle D, having radial tubes of small bore E leading from its lower edge to the walls of the still and passing over or near the cooling coils.

From the bottom of box D up through its top leads a pipe F which pass% out through the wall of the still, Where it is formed into several coils Gr and continued by pipe H to the box or compartment K having baffles L at the top near its outlet. The coils G are surrounded by a jacket in series with the cooling coils C on the inside of the still.

From the baflied into a reservoir or chamber P. From this latter acapillary tube Q whose open end is well within the inlet 0 is employed to carry the liquid refrigerant over to the refrigerating chamber which is not here shown.

he arrow 1 indicates the normal level of the solution in the still at the moment when the distillation period begins, and the arrow 2 its level at the end of such period. It will be observed that the open ends of the tubes E are somewhat below the level first named. I have omitted from the illustration all parts not directly concerned with my present improvement as they are well known and may readily be suppliedby those skilled in this art. From the general description of the invent-ion given above the operation of 'box K a pipe M leads to. the condenser N and is continued by pipe 0 the device will now be apparent. It need only be noted that the tube (,2 is of small cross section so as to enable the pressure to rise to a point at which liquid actually collects, and that it enters the inlet tube 0 which leads directly from the condenser, thus permitting a clear drain of the reservoir or intermediate chamber P.

This apparatus has proved to be of great practical value. Equipped with the usual appliances for automatically controlling the application of heat to the still and of cooling water either to the coils in the still or those of the condenser, and supplied with a suitable refrigerant such as ammonia, and with an absorbent therefor, its operation is satisfactory. to a high degree, absorption being established when necessary with great promptness and completeness.

What I claim as my invention is:

1. In a refrigerating apparatus, in combination, a still, cooling coils therein, a box or compartment in the dead space at the top of the still with outlets leading therefrom to points below the normal level of the solution but where they will discharge on the lowering of such level, upon the cooling pipes, a box or compartment without the still connected with that Within the same by pipes adapted to be artificially cooled at the end of the distillation periods.

2. In a refrigerating apparatus, in combination, a still, cooling coils therein, a box or compartment in the dead space at the top of the still having radial tube outlets of small bore extending to points below the normal level of the solution and in proximity to the cooling coils, a box or compartment above the still connected to that within the dead space and cooling means surround ing such connection.

3. In a refrigerating apparatus, in combination, a still, cooling coils therein, a box or compartment in the dead space at the top of the still, radial tubes extending from its bottom toward the walls of the still Where they will discharge on the cooling coils, a box or compartment above the still, bafile plates on the outlet thereof, a pipe connecting the two boxes named, and'a cooling jacket surrounding the same. 1

4. In a refrigerating apparatus, in combination, a still, cooling coils therein, a box supported in the dead space in the upper part of the still, radial tubes leading from the-bottom of the same to points below the normallevel of the solution and near the cooling coils, a pipe leading from the bottom of said box through the wall of the still, a cooling jacket surrounding the same, and a ballied box above the still to the bottom of which the said connecting pipe is joined.

5. In a refrigerating apparatus, in combination, a still, cooling coils therein, a copper box in the dead space within the still,

lift

aea e'ee radial tubes of small bore extending from near the bottom of the same to points below cooling coils, a baflled box or compartment above the still, a pipe leading from the bottom of the box within the still to the bottom of the bafiled box, a vWater jacket surrounding the said pipe, and connected with ing a portion of the liqiior-di iven over by Y t e recess of distillation a means for returnlng'such stored liquid'a t the distillation per od, a means FREDERICK e. REYES. 

